Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

Abstract

Blends of starch/polyester have been of great interest in the development of biodegradable packaging. A method based on multiple responses optimisation (Desirability) was used to evaluate the properties of tensile strength, perforation force, elongation and seal strength of cassava starch/poly(butylene adipate-co-terephthalate) (PBAT) blown films produced via a one-step reactive extrusion using tartaric acid (TA) as a compatibiliser. Maximum results for all the properties were set as more desirable, with an optimal formulation being obtained which contained (55:45) starch/PBAT (88.2 wt. (%)), glycerol (11.0 wt. (%)) and TA (0.8 wt. (%)). Biodegradable plastic bags were produced using the film with this formulation, and analysed according to the standard method of the Associação Brasileira de Normas Técnicas (ABNT). The bags exhibited a 45% failure rate in free-falling dart impact tests, a 10% of failure rate in dynamic load tests and no failure in static load tests. These results meet the specifications set by the standard. Thus, the biodegradable plastic bags fabricated with an optimised formulation could be useful as an alternative to those made from non-biodegradable materials if the nominal capacity declared for this material is considered.

PBAT/TPS‐nanowhiskers blends preparation and application as food packaging

“…The analyses were performed using a low‐intensity light beam, 5–10 kV. For better visualization of the image, samples were metallized with a thin layer of gold . ImageJ 1.39u (Wayne Rasband, National Institute of Health), an image analyzing software, was used to measure the diameter of the starch granules.…”

Polyvinyl alcohol films with different degrees of hydrolysis and polymerization

“…Tensile strength indicates the resistance of the material at the point of rupture during the tensile test (OLIVATO et al, 2013), and in this work was not possible to establish a relationship between tensile strength and the DH or DP of PVA. a Results express in mean (± standard deviation).…”

“…Glass transition temperature (Tg) is an important parameter in determining the mechanical properties of amorphous and semicrystalline materials, when submitted to a temperature above their Tg, the materials are in the elastomeric state and below Tg they are in the glassy state. The chains have increased mobility in the elastomeric state, and the physical and mechanical properties are strongly affected (OLIVATO et al, 2013;SHIRAI et al, 2013). Films based on PVA with higher DH presented more interactions between its polymer chains, resulting in lower molecular mobility and higher Tg values, as observed in Table 5.…”

Compostabilidade de embalagens biodegradáveis

“…O Departamento de Bioquímica e Biotecnologia, por exemplo, pesquisa a produção de bandejas biodegradáveis a base de amido de mandioca, que podem substituir bandejas de isopor em certas aplicações que envolvem um descarte rápido (SILVA et al, 2013;VERCELHEZE et al, 2013;MATSUDA et al, 2013;MARENGO;MELLO;. Já o Departamento de Ciência e Tecnologia em Alimentos desenvolve filmes a partir da blenda entre amido e poli (butilenoadipatoco-tereftalato) -PBAT, ou ainda ecoflex®, como é comercializado pela BASF (BASF, 2012) -dos quais se pode produzir sacolas plásticas de mercado, convencionalmente feitas a base de polietileno de baixa densidade (BRANDELERO; OLIVATO et al, 2013;NOBREGA et al, 2013;OLIVATO et al, 2014;GARCIA et al, 2014).…”